Helical wrap memory



Oct. 27, 1964 .1. D. BLADES 3 HELICAL. WRAP MEMORY 4 Sheets-Sheet 1Original Filed July 14, 1958 JOHN D. BLADES ATTORNEY Oct. 27, 196% J. D.BLADES 3,154,769

HELICAL WRAP MEMORY Original Filed July 14, 1958 4 Sheets-She 2 I ill52b 5b 2m I jg 4 I INVENTOR.

JOHN D. BLADES I BY AT RNEY Oct. 27, 1964 J, D. 'BLADES 3,154,769

HELICAL. WRAP MEMORY 4 Sheets-Sheet 5 Original Filed July 14, 1958 WRITE[O4 SELECT 42c 43d S STORAGE UNIT READ v 6 PULSE 2 1;: 350 350 2% 3gb3gb SOURCE 70 I 72 73 7| DATA //l05 DATA CONTROL SOURCE UTILIZATIONSIGNAL 65 DEvIcE souRcE 7 o6 7 v6 Fig. 6

6 330 23c 36a 33b 23b 36b 420 FOUR-BIT 43b '1- F 7 42c STORAGE uNIT 42dTo -1 t 240 3 2; 350 2 35b 35b 70 74 I LIL .L. INVENTOR. 76 JOHN D.BLADES CLEARING PULSE BY SOURCE W :1 m

ATTORNEY United States Patent 3,1545% nLlCAL WRAP MEll EQRY .lohn 1).Blades, Stafford, Pa, assignor to Burroughs Corporation, Detroit, Mich,a corporation of Michigan Continuation of abandoned application Ser. N748,4ii5, July 14, 1958. This application Nov. 7, 1962, Ser. No.

26 Claims. (Cl. 346-174) The present application is a continuation ofapplication Serial Number 748,405, filed July 14, 1958 and nowabandoned.

it is known in the arts of electrical computation, data handling andprocessing, and digital control to store items of information, each itemhaving one of two possible values, by magnetizing ferromagneticmaterials so that each unit of the material remains in one of twopossible states of magnetization corresponding to the value of t e itemof information that the unit of material is to represent. These units ofmaterial may be discrete, such as toroidal cores, or may be part of acontinuous piece of ferromagnetic material in which divisions into unitsoccur simply as a result of the means employed to magnetize the materialor to detect magnetization of the material. Conventional magnetic tapesand drums exemplify the second class. Perforated plates of magneticmaterial threaded with conductors constitute a kind of intermediatebetween the two classes in that the number of units is determined by thenumber of holes but the boundaries between the units are not discretelydetermined by physical boundaries of the material. it is a convenienceto employ magnetic materials whose physical shape need not be discretelyformed to demark the boundaries within which specific units ofinformation may be stored.

Certain ferromagnetic materials may be so processed that they possess anaxis of preferred magnetization, so that in the absence of externalmagnetizing fields they remain magnetized in one of the two possiblesenses along that axis, which may be simply denoted the magnetic axis.This behavior results a hysteresis loop which is substantiallyrectangular, since the material will tend to remain in its originalstate until an applied external field is sufiicient to drive it from theorig nal state, whereupon it will tend to change to the other stablestate.

It is well known that application of stress to certain ferromagneticmaterials will produce such anisotropy and a preferred direction ofmagnetization even if none existed without the stress. To apply this ina macroscopic scale, as by mounting a sizable sample of material betweenclamps and applying stress, has the disadvantage that it is difficult toapply stress uniformly by such means, and to preserve it at its desiredvalue. However, it is possible to produce a sumciently uniformdistribution of stress by such means as rolling an alloy in a strip andnot relieving stress by subsequent annealing. In parti ular, an alloy ofapproximately 4 percent molybdenum, 79 percent nickel, and the remaindersubstantially iron, which is well known in the art of magnetics, ifrolled into a thin strip and not annealed after rolling shows apreferred direction of magnetization along the direction of rolling.Reference: R. A. Tracy, p. 164, Proceedings Eastern loint ComputerConference, 1956. Certain other materials are known which, whilepossessing the requisite magnetic properties, are either physicallyinflexible or suffer impairment of their magnetic characteristics ifstressed or deformed after processing. Ferrites are examples of thefirst category, and certain alloys are examples of the second category.

My present invention pertains to the use of materials in the categoriesabove described for the storage of information in such a manner that thenumber of bits or elements of information which may be stored is wellice in excess of the number of pieces or assemblies of ferromagneticmaterial employed for such storage, without requiring that physicalboundaries be formed in the pieces of ferromagnetic material to delimitthe regions in which each element of information is stored. Moreparticularly, it pertm'ns to the storage of various bits of informationat various points along the length of one dimension of such a piece offerromagnetic material. It is usually desirable to minimize the totalvolume of magnetic material employed, since the energy required to alterthe magnetization of a given material is proportional to the volume. If,as is here proposed, different parts of a length of magnetic materialare to be magnetized and reversed independently of other adjacent parts,it is also desirable that such parts be long in the direction of theflux relative to their dimensions at right angles to such direction, inorder that the demagnetizing effect of the poles at the boundariesbetween two differently magnetized parts may be minimized. Theseconsiderations suggest that the cross section of the magnetic materialbe minimized; but this requires that, for a given maximum flux density,the total flux be minimized. Since the voltage induced by flux reversalat a given speed is proportional to the product of the total flux by thenumber of turns linked with the flux, such product being conventionallyknown as the linkages, it appears that it is desirable to maximize thenumber of times the given fiux is linked with the conductor in whichvoltage is to be induced. in my present invention I achieve a beneficialincrease in the number of linkages by wrapping or interwrapplng orinterweaving conductors with pieces of ferromagnetic material in variousways suited to the particular characteristics of various magneticmaterials, and in manners well suited to ease of assembly, and to themechanization of many of the steps of such assembly. As a result of thesimplicity of assembly, it is possible to achieve great compactness fora given storage capacity by the practice of my invention.

One form of my invention consists in wrapping, around one or moreconductors as an axis, a strip or tape of ferromagnetic material havinga direction of preferred magnetization so that current passing throughthese central conductors will produce a magnetizing field lyingapproximately parallel to the surface of the tape, but at an angle withthe preferred direction of magnetization of the tape, and providingother conductors capable of producing, by passage of electrical currentthrough them, a magnetizing field parallel to the surface of the tapebut at a different angle with the preferred direction of magnetizationof the tape. The latter conductors may he turns wrapped around some partof the assembly of tape and central conductors, and thus be capable ofproducing a field component parallel to the central conductors, andorthogonal to the field produced by the central conductors. it isevident that it is possible to choose the magnitudes and senses ofcurrents through the central conductors and through the surroundingconductors such that the field of the central conductors alone or thefield of the surrounding conductors alone will not sulfice to alter themagnetization of the tape; but where the two fields exist together, asat the place where the surrounding conductors circle the wrapped centralconductors, the combined fields will sufiice to alter the magnetizationof the tape in that vicinity only. Thus, the number of separatelyidentified and used bistable entities may greatly exceed the number ofphysically separate ferromagnetic pieces. In particular, an array may beformed of a number of separate wrapped central conductors physicallyparallel to each other; and surrounding conductors may be provided byweaving them as a woof upon the wrapped axial conductors as a warp.Adjacent woof wires woven in opposite sense, may be connected in seriesand will constitute the equivalent of a number of single turns inseries, one around each warp wire. Thus, application of current to aselected central conductor and a selected woof loop will permit controlof the magnetization of the tape at the nearest juxtaposition orcrossing of the two selected conductors.

If current is passed through a helically wrapped tape with successiveturns insulated fromeach other, the current will tend to demagnetize thetape by producing a magnetizing field at right angles to the axis ofeasy magnetization and will permit a relatively weak field subsequentlyto magnetize the tape along the said axis.

Thus, the recording of data may be effected by restoring all the tapearound a central conductor to a reference state (the zero state, inconventional computer vernacular) and then recording a signal (a one) bypassing current through the central conductor and current through aselected surrounding conductor so that the magnetization of only thatpart of the tape adjacent to both conductors is reversed. To determineat some future time whether a signal (a one) has been stored there, acurrent of opposite sense may be passed through the surroundingconductor, sufliciently greater in magnitude than the current used torecord the signal so that the greater current in the non-axial conductoralone will restore the adjacent portion of the tape to the reference(zero) state. The change of magnetizaiton will induce a voltage in thecentral conductor which voltage may be detected to determine that asignal has been stored in that particular element of the tape. Theinduced voltage will be relatively large because of flux linkagesbetween the tape and the central conductor will be multiplied by thewrapping of the tape around the central conductor.

The second form of my invention is intended particularly for convenientapplication of the principles of my invention to the use offerromagnetic materials which are too inflexible to bend readily or at asmall radius, or which suffer deterioration of their desired propertiesfrom such treatment. It is clearly not desirable to wrap suchferromagnetic materials around a central conductor, particularly one ofsmall dimensions, in order to increase the number of linkages by theembodiment of the first form of my invention. Instead, in this'secondform I achieve a large number of linkages between conductor andferromagnetic material by wrapping the conductor helically around asuitable central core. Such a wrapped core forms a convenient primaryassembly which may readily be further assembled into data storagedevices of characteristics varying according to need. Another form of mypresent invention is produced by twisting magnetic material and corearound each other. This requires that the magnetic material be somewhatflexible, but does not require such great deformation as is necessary ifthe magnetic material is to be wrapped around a straight centralconductor. The second and third forms of the present invention thusimpose simple mechanical and geometric requirements on the magneticmaterial, and impose requirements for flexibility, shape convenient forwrapping, and the like properties, upon conductive materials which, inthe conventional art, are usualy metals noted for ductility,flexibility, and malleaoility.

Accordingly, one object of my invention is to provide a mechanicallystatic ferromagnetic binary data storage means capable of recording databy selective coincidence of currents in separate circuits, in suchfashion that the number of elements of information stored may exceed thenumber of individual pieces of ferromagnetic material provided.

Another object of my invention is to provide a ferromagnetic binary datastorage means capable of simple and rapid assembly at least partly bymachines or principles well known and proven, as weaving machines.

Another object is to provide a ferromagnetic binary data storage inwhich the ferromagnetic material may be of standard commercial form andmay be applied by simple mechanical operations not calculated to produceany particular stresses in the material.

Another obiect is to provide a ferromagnetic binary data storage inwhich a single conductor in the simplest embodiment may be readilyreplaced by several conductors whose separate effects may be caused toassist or oppose each other, thereby permitting greater latitude in thedesign of the selection system.

A further object of my invention is to permit the convenient use ofmagnetic material of various degrees of flexibility or stiffness andvarious cross-sectional shapes as a storage medium employing a smallvolume per unit of information with a relatively high read-out voltage.

Another object of my invention is to extend well-tried principles ofvoltage induction to the improvement of large-capacity inexpensivestatic data storage devices.

Further objects and advantages of my invention will appear in the courseof the following description,

In the attached drawings:

FIG. 1 represents a physical arrangement or" central conductorsheiically wrapped with ferromagnetic material, according to myinvention;

FIG. 2 represents an alternate physical arrangement of centralconductors and ferromagnetic material;

FIG. 3 represents elements of FIG. 1 or FIG. 2 wound with surroundingwindings according to my invention;

FIG. 4 represents elements of FIG. 1 or FIG. 2 woven with surroundingwindings according to my invention;

FIG. 5 illustrates a distribution of magnetization of ferromagneticmaterial;

FIG. 6 represents schematically the use of the assemblies of FIG. 3 orFIG. 4;

FIG. 7 represents an addition to the functions of FIG. 6;

FIG. 8 illustrates a mode of applying conductors to the magneticmaterial in the practice of my invention;

FIG. 9 illustrates a modification of the mode of applying conductors tomagnetic material in the practice of my invention;

FIG. 10 illustrates an alternative mode of assembling magnetic materialwith attached conductors into a data storage assembly, in accordancewith my invention; and

FIG. 11 illustrates an arrangement for the utilization of my inventionfor the recording, reading and regeneration of stored data.

In FIG. 1, 31 and 34 represent electrical conductors with respectiveterminals 32 and 33 for 31, and terminals 35 and 36 for 34. As apractical matter they must be insulated from each other, and from thetape 21' (to be further described) if it is conductive. Such insulationcan be achieved by insulating 31 and 34 and 21, or any two of thesethree; for many applications it is permissible to have contact between31 and 34 and 21 at points always identical in potential so that noundesired circulation of current between or among the various conductorswill occur. The art of electrically insulating circuits to preventundesired or deleterious circulating currents or short circuits is overa century old and well understood.

In all of the following, it is to be understood that conductors orconducting parts are provided with such insulation as the art shows tobe required to prevent the flow of current by undesired paths.Consistently therewith, no insulation will be shown in the drawingssince the disclosure of my invention would be rendered less easy tounderstand if the presentation of its basic principles were beclouded bythe inclusion of matter so well known in the art.

The tape 21 of FIG. 1 is ferromagnetic, having a sub- 'stantiallyrectangular hysteresis loop and having a magnetic axis, or direction ofpreferred magnetization (as indicated by double-headed arrows)substantially parailel to its length. It is so wound around the centralconductors 31 and 34 that its magnetic axis is approximately a helixabout the central conductors. It is known that cold rolled andunannealed strip of so-called molydirection of the magnetic axis of tape21a.

permalloy, consisting of approximately 4 percent molybdenum, 79 percentnickel, remainder substantially iron, in thickness of a fraction of athousandth of an inch, has the characteristics described for tape 21 andmay be wrapped as described without impairing these characteristics. Myinvention does not depend upon the use of a particular material, and thedisclosures herein are applicable to any material having the magneticproperties described in the preceding. Thus, for example, and adhesivenon-metallic tape coated with particles of nonconducting ferromagneticmaterial so aligned as to possess the magnetic axis as above describedmay replace the metallic tape Where the ferromagnetic material is notalso used as a conductor. For replacement in applications where themetallic ferromagnetic material is used as a conductor, anon-ferromagnetic conductor may be attached to the non-conductiveferromagnetic wrapping and used as an equivalent conductor. The tape 21may be Wound with a lap (in which case, if tape 21 is conducting,successive turns should be insulated from each other to minimize eddycurrents) or, if it is desired to increase the total magnetic fluxproduced by magnetization of the tape 21, several pieces may be wound inparallel or superposed. The central conductors repre sented are two;depending upon the particular circuitry desired, a single centralconductor or a multiplicity thereof may be used.

FIGURE 2 shows the same central conductors 31 and 34 indicated in FlG.l. The wrapping 22, however, replaces the helically wrapped tape 21.Wrapping 22 is of the same properties as tape 21 with the exception thatits magnetic axis is oblique to both of the principal dimensions of therectangle which is its shape. As illustrated in FIG. 2, 22 may beWrapped in a simple approximately right cylindrical sleeve, yet itsmagnetic axis will be substantially helical around the centralconductors. Possibilities of substitution apply to wrapping 22 as citedfor tape 21, with such obvious modifications as the known art woulddictate.

The separations shown in the figures between the central conductors andthe ferromagnetic wrappings are exaggerated for clarity of disclosure;the ferromagnetic wrappings will ordinarily be as close as feasible tothe central conductors.

FIGURE 3 represents two elements as of FIG. I, wrapped with solenoidalwindings 41a, 41b, 41c and did over the ferromagnetic wrappings 21a and21b, duplicates of 21 of FIG. 1. Specifically, central conductor 310,having terminals 32a and 33a, and central conductor 34a, havingterminals 35a and 35a, are wrapped by tape 23a, having terminals 23a and24a. The second element is similarly described by substituting finalletter b in place of a in all designations of the preceding sentence.Around the upper half (in FIG. 3) of 31a, 34a, and 21a there is woundsolenoid 41a, having initial terminal 42a and final terminal 43a; andaround the lower half of 31a, 34a and 21a there is wound a solenoid 410having initial terminal 42c and final terminal 430. Similarly, on theassembly of 31b, 34b and 21b there is wound solenoid 411) as thehomologue of 41a and solenoid lid as the homologue of 410, with terminaldesignations completely homologous and differing only in final letttersas represented. Terminal 43a is connected to terminal 42b, and terminals43c is connected to terminal 42d, as represented in FIG. 3. Thus,solenoid 41a is in series with solenoid 41b; and solenoid 410 is inseries with solenoid did.

It is apparent from the known laws of electromagnetics, uponconsideration of FIG. 3, that a current fiowing through a centralconductor 31a, will produce a magnetizing field approximately parallelto the conductors of solenoid 41a, and therefore having a component inthe A current flowing through solenoid 41:: will produce a magnetizingfield inside the solenoid substantially parallel to the centralconductor 31a, and therefore having a component in the direction of themagnetic axis of 21a, the term magnetic axis here and elsewhere in thisspecification signifying the direction of easy or preferredmagnetization of the ferromagnetic material. The total magnetizing fieldproduced by current in central conductor 31a and by current in solenoid41a may, by suitable choice of current values, be substantially parallelto the magnetic axis of tape 21:! and in excess of the coercive forceeverywhere in those portions of Zia in the immediate vicinity ofconductor 31a and solenoid so that those portions of tape 21a will bemagnetized in the direction of the resultant field, even if they wereoriginally magnetized in the opposite direction.

In the situation thus far considered, that part of tape 21a lyingsubstantially inside solenoid 41a will be subjected to a magnetizingfield from the current in conductor 31a; and that part of tape 21b lyingwithin solenoid 41:) will be subjected to a magnetizing field from thecurrent flowing through 41a if (as FIG. 3 suggests by theinterconnections represented) that current also flows through 4112.However, it is well known that it is possible so to choose themagnitudes of current in central conductor 31:; and solenoid 41a thatonly where the fields produced by these two currents are presenttogether in substantial amplitude (as distinct from the faint fieldswhich would exist at a distance) will the magnetizing field be greaterthan the coercive force of the material of 21a and thus sufficient toreverse the magnetization of the material of 21a. Thus, the portion oftape 21a inside solenoid 41c, and tape 2112 will not be afiected by themagnetizing fields here proposed.

it is thus evident that by selective passage of current through acentral conductor and a pair of solenoids in series, corresponding towhat is known in the art as row and column selection, it is possible tocontrol independently the state of magnetization of two distinct partsof ferromagnetic material 21a and two distinct parts of its homologue21b. In brief, a binary storage device with a capacity of four bits orbinary digits has been described. It is apparent from the known art thatthe selecting field may be produced by current through several centralconductors, and that multiple solenoidal windings may be superimposed sothat their fields add in a given space. Special attention is, however,invited to the fact that the tape wrapping itself (21a, 2311)) forms asolenoidal winding obviously coincident with itself, and havingterminals 23:: and 24a, and 23b and 24-5.

The operation of winding successive solenoids over several wrappedcentral conductors, while capable of performance by mechanical devices,is of several distinct steps: winding on one conductor, indexing to thenext conductor, winding on that, and so forth. Weaving is a somewhatsimpler operation in that the movement of the woof is continuous, exceptfor reversal at the end of the path, and the shifting of the warp is asimple alternation. Furthermore, weaving techniques are thebeneficiaries of some millennia of experience and, recently, of twocenturies of intensive development. Except ror some slight additionaletfective distributed capacities, there is little ditference if awinding of N turns is formed by winding all turns in succession or byproviding a half turn, carrying the conductor off to some other points,and returning to the point of interest to apply another half turn, andso forth. This is actually what is accomplished by weaving theconductors of the solenoids as a Woof on the wrapped central conductorsas a warp. The only major difference between weaving and windingsolenoids is that, while successive solenoids may be wound with the samesense, the nature of weaving produces alternate reversals of polarity.Thus, FIG. 4 represents two units as depicted in FIG. 1 with theequivalent of solenoids 41 provided by weaving of weft conductors (whichare represented as joined by twisted splices), the upper system of Weftconductors being marked le and the lower 41' Corna voltage will beinduced in conductors Illa and 3 similarly for reversal of magnetizationin 21b, ther parison of FIGS. 3 and 4 will reveal that in FIG. 3 pointson the left-hand and right-hand assemblies are strictly homologous,correspondingly numbered points serving similar functions at homologouslocations, with the dir" ference in identity indicated only by thepostliterals, a, b, c or d. in FIG. 4, the reversal of sense of the woofwindings on alternate warps causes a top-to-bottorn reversal ofelectrically homologous points; thus 32a is at the bottom, 32!; is atthe top, of FIG. 4. The electrically homologous points in FIGS. 3 and 4have been given identical or obviously cognate numbers, so that the demonstration of the use of the invention in FIG. 6, and the accompanyingdescription, will apply correct references to either FIGS. 3 or 4. a

FIG. 5 represents a tape heliXol' three turns, each turn beingseparately magnet zed as indicated by the arrows with the letters S andN representing the approximate locations of north and south poles in thetape. I The arrows external to the tape 21 indicate the general pathwhich the turn fiux must follow through'the space surrounding the tapeto complete the magnetic flux pah. This indicates the general situationwhich might exist if the two extreme loops contained in the reference orzero value of information and the center loop contained the alternate orone value of information. it appears clearly that the return paththrough space is made shorter by the winding of the tape 21 in a helix.

In FIG. 6, the rectangle llli' represents the assembly shown in detailin FIG. 3, or the equivalent one shown in detail in PEG. 4, it beingunderstood that 42a, 420, 4317, 43d of FIG. 6 read upon 42 62, 42%, 43%,4 3%.,

respectively of FIG. 4. Control signal source 631 is a devicefor'producing in the requisite sequence the actuating signals requiredby the items marked E li, t 3%, inclusive. In 'a computer i127, controlsignal source ldl would ordinarily be a part of the central controlsystem of the computer proper. At the beginning of a complete cycle ofuse, control signal source lll transmits a signal over path 62 to readpulse source Hi2, causing it to transmit through path 67 a read pulse towork select tea, which transmits the read pulse through path 68 or path69 to terminal 42a or 420, respectively. The choice of path and terminalwill be determined by the control signal sent simultaneously orpreviously over path 63 from control signal source 1531 to word selectElle. Let it be assumed that path 68 and terminal 42:! receive the readpulse. The pulse will flow from terminal 42a through thewindiugs aboutthe upper parts of tapes Zla and Zlb to terminal 43!) to ground, asconvntionaliy represented. This current pulse is produced of such magnitudethat it is capable, without the assistance of other currents, ofmagnetizing the portion of tapes and 215 near terminals 234i and 23b,respectively, in the direction of. these terminals. magnetic field inthe direction of 23a and 23b, respectively. The component of suchlfieldalong the magnetic axes of Zia and 211), respectively, produces themagnetization described. It" the magneti ation operation involves thereversal of magnetization in any part of 21a,

e if

be induction of voltage in conductors 31b and 34b.

. ever, the control signal source lt ll is so constituted that for theclearing operation it does not provide on either path 64 or path -55 asignal to data sourc 3% or data utilization device 1%, respectively, toclose their respective circuits with the respective conductors named.Therefore the induction of voltage in the central conductors during theclearing operation produces no efi'ects.

' 'Aftcr the completion of the clearing operationthus described, the twounits of storage thus cleared are con- Q sidered to:contain logicalzeros, or to be'in the reference 1 condition. The other two units oftape nearest to to fnals 24a and 25%!) operation.

may be cleared similarly, by a sin:

This it does by producing a strong axial The next typical operation iswriting of data. Control signal source 161 sends a signal over path 61to write permit 163, which by path 66 transmits throughzword select 1%and paths 6% or 69, a current pulse opposite respectively, but notsulficient alone to reverse the magnetization of those portions of thetape. However, while the write permit current pulse exists, controlsignal source 1 .31 transmits over path 64 to datasource a signal whichcauses data source to transmit binary information signals over paths 70and 71-to terminals 35a and 35b;

respectively. For the polarities of windings and conduc tors shown,these information signals should be negative for the signal having a onevalue, and zero for a signal having a zero or reference value.

Letit be assumed that the signal of path 70 has a one value, and that ofpath 71 has a zero value. pulse representing the one signal will flowfrom terminal 35a through conductor 34a, producing a field circular orsolenoidal about the conductor, toward theleft of FIG. 3

above the central conductor 34a, and therefore producing a magnetizingfield having a component tending to magnetize tape 21a downward.However, the magnitude of-the signal is not suificient to produce thiseffect by itself. Therefore the tape 21a will be magnetized downward inits upper part where negative write permit current entering at terminal42a also produced a field; but thetape 21a in the lower half where thereis no auxiliary field will remain magnetized upward in the referencecondition. Similarly, no part of tape 215 will be subjected to twofields simultaneously, and therefore the part of the tape 21b nearer toterminal 23b will remain in 'the'reference or zero state appropriate tothe zero value of signal assumed for path 71. It will be readilyapparent how one or zero values of signals may be recorded in any of thefour tape regions.

The final operation requiring illustration in the use of thisin'ventionis reading of the data stored by the writing operation. Let it beassumed that the data whosewriting is described in the precedingparagraph'is that to be read. Controls'ignal source 191 sendsby. path 63to a word select 194 a signal causing word select 1tl4'to open path 68to terminal 4.2a. Control signal source 101 sends by path 62 to readpulse source 102 a signal which causes read pulse source Hi2 totransmitby path 67 a read-out pulse through word select Y164- and path 68 toterminal 420.. The read-out pulse passes to ground through the windingsof 197, detailed in FIGS. 3 and 4, and causes the portions of tapes 21aand 21b nearest to terminals 23a and 235, respectively, to be driven tothe reference The tape portion .of' 21a which 'was 191 transmits by path65 to data utilization device res a signal causing it to open the signalpath 72and 73 so that any signals appearing at terminals 32:: and 32bmay enter the circuits of data utilization device 196. In the j presentinstance, a voltage will appear in path 72 but none'f in path 73. f Thedata utilization device will :makeuse of 's stored information inaccordance with the purposes which it is constructed.

The negative current The foregoing describes in detail the mode ofperforming the standard functions of a binary data store. The known artwill indicate possibilities of vast increase in the store size and thenumber of binary values capable of being stored, and numerous othervariations which are comprehended in my invention. It also appears thatcurrent through tape 21 will produce a magnetizing field tangentialaround the tape at right angles to its axis of easy magnetization. Thusa separate circuit may be provided to demagnetize the tape and render itcapable of being restored to the zero or reference state ofmagnetization by the application of a relatively weak axial magnetizingfield. A convenient auxiliary clearing circuit may be provided to permitthe tape to be restored to its reference or zero condition by amagnetizing field which, in the absence of the auxiliary circuit, wouldnot be suificient to produce such restoration. A specific means of doingso is illustrated in FIG. 7. The auxiliary apparatus is as in FIG. 6 andis not here repeated. Four-bit storage unit 107 is represented with thealteration from FIG. 6 that terminals 23a and 23b are connected toground, conventionally represented and there is also represented aclearing pulse source 1%. Terminals 24a and 24b of 197 are representedas connected to 168 by conductors 74 and 75, respectively, and controlline 76 is represented as connecting clearing pulse source 158 tocontrol signal source 191 of FIG. 6. Other connecting lines, 68, 69, 70,71, 72 and 73 are connected as in FIG. 6. The only difference betweenFIG. 6 and FIG. 7 is in the addition of 108, and the connections made toterminals 24a, 24b and 23a and 2312, as represented.

The manner of operation of the arrangement represented in FIG. 7 permitsclearing of data stored in tape 21a or in 2112, as follows. A controlsignal generated by control signal source 1%1 is transmitted by line 76to clearing pulse source 108. In response to such control signal,clearing pulse source 193 applies through (e.g.) line 74 to terminal 24aa current pulse which passes through the helical winding of tape 21a toterminal 23a and thence to ground. This current pulse is specified assufficient in magnitude to produce a magnetizing field sufficient todemagnetize all of tape 21a. ternatively, clearing pulse source 108 maybe caused to apply a similar current pulse to tape 21!) via line 75 andterminal 2412. It now by the devices and logic of FIG. 6 alreadydescribed there are applied to terminals 42a and 42c of 107 pulses ofthe same polarity as the read pulses described in connection with thedescription of FIG. 6, but of suitably lower amplitude so that they areinsuficient by themselves to reverse the magnetization of tape 21a or215 when no demagnetizing field has been applied to those tapes, whenthese lower amplitude pulses will be able to cause the demagnetizedtapes to return to the reference or zero condition. Thus by selectiveapplication of current to terminals 24a or 2%, it is possible toselectively clear a particular digit store in both of the words of N7.This is sometimes desirable. Obviously, the employment of theferromagnetic tape as a conductive path is susceptible of manyvariations, according to the known art.

In FIG. 8, 121 represents a ferromagnetic core having a direction ofeasy or preferred magnetization substantially parallel to its ax s, asindicated by the double-pointed arrow in the figire, and possessing asubstantially rectangular hysteresis loop for magnetizing fields orcomponents thereof applied along its axis. The ordinary processes ofdrawing a w le through a die tend to produce crystal orientation andinternal stresses disposing many ferromagnetic materials to suchmagnetic characteristics. For example, nickel wire not annealed afterdrawing demonstrates such properties. Conductors 131 and 131' differonly in shape of cross-section, 131 being of conventional circularcross-section, 131' being or flattened cross-section which may be moreconvenient in certain circumstances. The significant point illustratedby the figure is that the conductors 1'51 and 131 are wound helicallyabout the central core 121 so that magnetic flux along or parallel tothe axis of 121 will be linked many times with the conductors 13-1 and131'.

FIGURE 9 represents another manner of securing such linkage, in whichconductor and ferromagnetic material are twisted about each other sothat it is not possible to identify either as axis. It is, of course,apparent that core 121 need not be of circular cross-section, nor needit be of one piece, but maybe composed of several pieces having theirlengths substantially parallel, regardless of whether they are simplyparallel to each other, or braided or twisted or otherwise intertwinedwith each other. Likewise, the fundamental disclosure by conductor 131is of a conducting path, which in many instances may most convenientlybe provided by a conventional insulated wire, but may be equally wellfurnished by equivalents such as a conducting spiral formed by paintinga spiral of metallic paint or metal compound around a suitableinsulating coating overlaying core 121, and processing the paintedspiral by any means required to render it a mechanically stableconductor.

In FIG. 10, there are represented two lengths of conductor-entwined core121a, 131a and 1215, '131b. A single length 1414: of conductor isindicated as wrapped as a solenoid around 121a, 131a and in a separatesolenoid around 121b, 131k. Similarly, a second conductor 141i) iswrapped in separate solenoids around 121a, 131a, and around 1211;, 131b.Current through conductor 131a will produce a magnetizing fieldsubstantially parallel to the length and thus to the direction of easymagnetization of core 121a; and current through conductor 141a willproduce magnetizing fields parallel to the lengths of cores 121a. and121b, respectively, but chiefly near the ends marked A, and having,indeed, their maximum values inside the solenoids formed by theconductor 141a. Similarly, current through conductor 1411) will producemagnetizing fields parallel to the lengths of cores 121a and 121b, buthaving their maximum values inside the solenoids formed by conductor1411). It now appears from the known art, and is abundantly taught bynumerous patents and other publications in the computer field, that itis possible to apply a first current through conductor 131a and a secondcurrent through conductor 141a of such magnitudes that the magnetizingfield component produced by either the first or the second current alonewill not equal the coercive force of the cores 121a. or 1221b; but thatwhere the fields produced by the two currents are both strongly present,as they are near the end A of core 1210, their resultant exceeds thecoercive force. If the coercive force is thus exceeded, and if it isopposite to the initial direction of magnetization of the core 121a, themagnetization of core 121a will be reversed in direction near the end Aof core 1210, without altering the magnetization of the other core 121];or that of the other end B or" core 121a. Similar procedures permit theindependent control of the direction of magnetization of the other threeparts of the cores 121a and 123th; obviously a larger number ofconductors analogous to 141a with a correspondingly greater number ofindividual solenoids in the system would permit the selection andindependent control of a larger number of separate elements of cores121. The number of subdivisions of a core 121 capable of separate andindependent re versal of magnetization will depend upon the possiblenumber of individual divisions within which the magnetizing field can beindividually con-trolled, and will therefore depend upon the exactdesign of the magnetizing coils, but the demagnetizing effect of thediscrete poles formed at each boundary between two senses or directionsof magnetization will determine how small an independent element may beand still be stable when magnetized in a sense opposed to that of itsneighbors.

it is apparent that, if a given sense of magnetization is assigned areference or zero significance, in accord With conventions of thepresent known art, an alternate or 'a particular equivalent solenoid.

one significance may be assigned to the reverse direction ofmagnetization. Thus, it is possible to apply to a given conductor e.g.1410, a current of suitable polarity and magnitude to 'drive the coreelements which con-tam a one and therefore were initially of reversedmagnetization will be reversed to the reference condition with acorresponding change of flux and the induction of a voltage inconductors 131. Alternatively, a current pulse as described, known inthe trade as a read pulse may be applied to a given wrapping conductor131a and any elements reversing from the one to the zero state willinduce voltages in the solenoids of conductors 141.

FIGURE 11 represents an alternative way of practicing my invention. Theoperation of winding solenoids around the wrapped cores tends to beexpensive and may therefore be undesirable. The operation of weaving awoof of conductors around the wrapped cores as a Warp is capable ofbeing made to produce a magnetic equivalent of the solenoids, althoughthe conductors thus intenwoven are not capable of being identified asparts of A desirable arrangement is that of FIG. 11 where horizontalconductor loops 141a, 1411:, etc. are representative of equivalents ofconductors 141 of FIG. and conductor loops 151a, 151b, etc. are woven atright angles to the 141 series of conductors. The wrapped cores 121a,131a and 121b, 131b, etc. are inserted diagonally witmn the loops ofboth the 141 series of conductors and the 151 series of conductors. Thuscurrent in either series of loops will produce a magnetizing field at anangle with the axis of the core 121.

The magnetizing field components from current in conductors of the 141series and the magnetizing field components-from current in conductorsof the 151 series will be at an angle to each other.

-FIGURE 11 includes a system using that embodiment of my inventionproduced by weaving of conductors and inserting wrapped cores therein,as just described above.

Cores 121a, 121b and 121a are shown wrapped with conductors 131a, 1311;and 1310, respectively. Around these are woven conductors 1416:, 141b,1410 and 1510, 151b, 1510. The multiplicity of passes of conductors 141and conductors 151 causes them to constitute the equivalent ofmulti-turn coils wherever they are woven around a core 121. It will beobserved that conductors 141 and 151 are so applied that wherever aconductor 141 is woven around a core 121,- a conductor 151 is alsowrapped around the core at approximately the same point. Also, since thearrangement of conductors shown does not lend itself to a uniform numberof such intersections in series in each conductor 151, they have beendeliberately connected so that every 151 conductor includes three suchintersections. The weaving technique produces alternate reversals ofwinding direction at each intersection, so the polarity of connection ofwindings 131 has been reversed at alternate cores 121 in order topreserve the same relative polarity of all windings at any given point.

The functional rectangles indicated in FIG. 11 are convenientrepresentations of equipment to perform certain functions, the art beingamply supplied with techniques for producing such devices; but it isextremely probable that in given application of my invention these samefunctions may be performed by circuitry also employed for theperformance of other functions not directly related with the practice ofmy invention, and not directly identifiable with the indicatedrectangles.

In FIG. 11, the clearing operation is initiated by a signal from controlsignal source 291 via line 163 to word select switch 204 which causes itto connect read pulse source 202 by line 1257 to a 142 terminal (forexample, terminal 142a, via line 172). A signal from control signalsource 2111 via line 162 to read pulse source 202 causes the latter tosend a read pulse by path 16'7- 204-172 to terminal 142a throughconductor 141a to 1'2 terminal 143a to ground. The read pulseis ofamplitude sufiicient to produce within the weaves of conductor 141aaround cores 121a, 1121b and 1210 a mag netizing field in excess 'ofthecoercive force, and therefore to set the upper ends of cores 121a, 121b,1210 to the reference or zero condition. Similar procedure may befollowed to apply read pulses to conductors 141b and 1410 to restore tothe zero condition the'core portions around which theyare woven. Datautilizatio'n device 296 is insensitive at this time to any voltagesappearing on conductors 178, 17?, 180.

Recording or writing is initiated by a signal from control signal source261 via line 163 to word select switch 2il4 which causes it to connectwrite permit 'pulse source 2113 via line 166 to a 142 terminal (forexample, 7

terminal 142a, via line 172). A signal from control signal source 201via line 161 then causes write permit pulse source 203 to transmit bypath 166-294-172 to terminal 142a a write permit pulse through conductor1410 to terminal 143a and ground. The sign of the write permit pulse isopposite to that of the read pulse, and its amplitude is such that itproduces at each volume surrounded by weaves of conductor 141a amagnetizing field insufficient alone to exceed the coercive force ofcores 121. While the write permit pulse continues, data source 205,incompliance with a signal received from control signal source 2111 vialine 164 applied information signals to lines 175, 176, 177 and thus toterminals 152a, 152b, and 1520, respectively of conductors 151a, 1511;and 1510. The convention applying to information signals may be that, ifthey represent the reference of zero value of information, they havenegligible amplitude, but if they represent the alternate 'or one value,they have some. predetermined amplitude.

Let it be assuemd that the information values appearing on lines 175,176 and 177 are, respectively, one, zero, one. The predeterminedamplitude of signal is required to be such that by itself it cannotproduce within the weaves of the 151 conductor through which it flows amagnetizing field in excess of the coercive force of the cores 121, butthat when combined with the magnetizing field produced by a write permitpulse flowing through the weaves of a 141 conductor, it can exceed thecoercive force of the core material and will cause the adjacent coreportion of 121 to reverse its magnetization to the alternate or onedirection, thus storing an information value one. Accordingly, the onesignal on line will cause local reversal of magnetization of the upperend of core 12117 to the one state; likewise the one signal on line 177will cause local reversal to the one state of the upper end of core121a. Core 1210 will remain in its reference or zero state because onlya negligible signal exists on line 176. Thus the specified informationis stored in the upper extremes of cores 121.

Recovery or reading of the stored information is accomplished by theselection of the proper 'word line by word select switch 264 incompliance with a signal received over line 163 from control signalsource 201. Let it be assumed that it is line 172 which is selected andtherefore connected to read pulse source 202 by way of line 167. Asignal from control signal source 2411 vialine 162 to read pulse source292 causes a read pulse to be sent by path 167-204-172 to terminal 142athrough conductor 1410 to terminal 143a and ground. As during the clearoperation, this pulse produces magnetizing fields at the upper ends ofcores 121a, 121b, 1216 sufiicient in magnitude and direction to causethem to return to or remain in the reference or zero condition.

Cores 121a and 12112, having been locally in the alternate V ings 131aand 1311) will accordingly have appreciable voltages induced in them andwill cause such voltages to appear on lines 178 and 179; only negligiblevoltage will be induced in conductor 1310 and appear on line 180. Datautilization device 266, having been made responsive to input signals onlines 178, 179, 180 by a control signal received over line 165 fromcontrol signal source 201, will receive the information thus recoveredfrom storage and utilize it according to the predeterminedcharacteristics of the data utilization device 2%.

Thus the functions essential to the util zation of a data storage devicehave been explained with respect to FIG. 11.

Obviously, the extreme flexibility and facility of permutation Whichhave rendered the digital computation, control and allied arts soprolific render it impossible to specify the many modifications of myinvention which will readily occur to those skilled in the art, in thelight of the disclosures herein; and, as has been indicated in theteaching of the use of my invention, the use of given circuitry toperform a large variety of functions at different times during the cycleof computer operation may Well render it desirable to perform bydifferent physical groupings of apparatus the functions hereindescribed. Such variations in application Without departure fromprinciples herein disclosed are intended to be included in the presentdisclosure.

What I claim is:

1. In a binary data storage device; first conductors; second conductorssubstantially at right angles to said first conductors and passingbetween alternate first conductors; and strips of ferromagnetic materialwrapped with third conductors and having a preferred direction ofmagnetization substantially parallel to their longest dimension locatedbetween said first conductors and said second conductors at an acuteangle with said first conductors.

2. A data storage device comprising a multiplicity of pieces offerromagnetic material having each a preferred direction ofmagnetization substantially along the length of each said piece, thesaid length of said piece being at least ten times its width and atleast ten times its thickness; conduction paths located substantiallyhelically around the length of each said piece as axis; and conductorswoven as woof upon said pieces of ferromagnetic material and saidconduction paths as warp.

3. A data storage device comprising first conductors and secondcondctors woven together as woof and warp; long pieces of ferromagneticmaterial having substantiahy rectangular hysteresis loops in the generaldirection of their lengths and surrounded by helically wound thirdconductors, the said pieces of ferromagnetic material and thirdconductors wound thereabout being inserted at acute angles with saidwoof and Warp and passing between said woof and said Warp at at leastsome of their crossings.

4. A binary data storage device comprising a multiplicity of pieces offerromagnetic material each capable of assuming bistable states ofmagnetic remanence representative respectively of stored binary logicalinformation, said ferromagnetic material having a preferred direction ofmagnetization substantially along the length of each said piece, thelength of each of said pieces being substantially greater than its widthor thickness, first conductors and second conductors so interwrappedwith said pieces of ferromagnetic material and with each other thatelectric current through any one of said first conductors will producein a discrete area of at least one of said pieces of ferromagneticmaterial a magnetizing field not parallel to the preferred direction ofmagnetization of said one piece of ferromagnetic material, and thatelectric current through one of said second conductors Will produce insaid discrete area of said one piece of ferromagnetic material amagnetizing field not parallel to the preferred direction ofmagnetization of said one piece of ferromagnetic material nor parallelto the magnetizing field produced by current through said firstconductor, orientation of the magnetic field effected respectively bysaid first conductor and said second conductor being such that theresultant of the said magnetic fields is substantially parallel to saidpreferred direction of magnetization of the ferromagnetic material insaid discrete area, said magnetic material in said discrete areaassuming one or the other of its stable remanent states in response tothe coincident flow of current in said first and second conductors.

5. A binary data storage device comprisin strips of ferromagneticmaterial each capable of assuming bistable states of magnetic remanencerepresentative respectively of stored binary logical information, saidferromagnetic material having a direction of easy magnetization parallelto its longest dimension and oriented in the form of a helix having aclosed magnetic path of easy magnetization which extends outside of saidferromagnetic material; conducting means situated respectively on bothsides of said ferromagnetic material but not piercing said ferromagneticmaterial, capable by coincident application of currents to saidconducting means of selectively altering the remanent magnetization ofselected parts of each of said strips; means for selectively applyingsaid currents to said conducting means to produce said selectivealteration of said remanent magnetization; and means for selectivelydetecting by voltages induced in said conducting means said selectivealteration of said remanent magnetization.

6. A bistable storage element comprising at least one central electricalconductor having wrapped therearound at least one strip of ferromagneticmaterial having a preferred direction of magnetization parallel to itslongest dimension and being capable of assuming bistable states ofmagnetic remanence representative respectively of stored binary logicalinformation, said strip of ferromagnetic material when wrapped aroundsaid central conductor exhibiting a prefered direction of magnetizationor magnetic axis substantially helical about said central conductor, anda multiplicity of solenoidal conductors wound around said wrappedcentral conductor as an axis, the solenoids thus formed being locatedsuccessively along the length of said Wrapped central conductor withoutoverlapping each other, drive means for applying current selectively toat least certain of said solenoidal conductors whereby said binaryinformation is stored along the length of said wrapped centralconductor.

7 A bistable storage element as defined in claim 6 characterized in thatsaid strip of ferromagnetic material is substantially rectangular incross-section.

8. A bistable storage element comprising more than one centralelectrical conductor having wrapped therearound at least one strip offerromagnetic material having a preferred direction of magnetizationparallel to its longest dimension and being capable of assuming bistablestates of magnetic remanence representative respectively of storedbinary logical information, said strip of ferromagnetic material whenwrapped around said central conductor exhibiting a preferred directionof magnetization or axis substantially helical about said centralconductor, and at least one other conductor forming a loop around theWrapped central conductors and approximately at right angles to saidaxis of said central conductors, drive means for applying currentselectively to at least said one of said other conductors whereby saidbinary information is stored along the axis of said wrapped centralconductors.

9. A bistable storage element as defined in claim 8 characterized inthat said one strip of ferromagnetic material is substantiallyrectangular in cross-section.

10. A bistable storage element as defined in claim 9 furthercharacterized in that the thickness of said one strip of ferromagneticmaterial measured along a radial line from the center of the centralelectrical conductor around 155 i which it is wrapped, is substantiallyless than the width of said one strip.

11. A bistable storage element comprising at least one centralelectrical conductor having wrapped therearound at least one strip offerromagnetic material having a preferred direction of magnetizationparallel to its longest dimension and being capable of attaining opposedstates of residual flux density in representing binary logicalinformation, said strip of ferromagnetic material when wrapped aroundsaid central conductor exhibiting a preferred direction of magnetizationsubstantially helical about said central conductor, a plurality ofdistinct electrical conductors axially spaced from one another alongsaid wrapped central conductor, each of said distinct conductorsencirclin said wrapped central conductor about discrete areas thereof,conditional current means for applying electrical signals respectivelyto said latter conductors and to said central conductor for effectingthe magnetization of said discrete areas whereby binary logicalinformation is stored in each of said areas.

12. A bistable storage element comprising at least one centralelectrical conductor in an unstressed condition having wrappedtherearound at least one strip of ferromagnetic material having apreferred direction of magnetization parallel to its longest dimensionand being capable of attaining opposed states of residual flux densityin representing binary logical information, said strip of ferromagneticmaterial when wrapped around said central conductor exhibiting apreferred direction of magnetization substantially helical about saidcentral conductor, a plurality of distinct electrical conductors axiallyspaced from one another along said wrapped central conductor, each ofsaid distinct conductors encircling said wrapped central conductor overdiscrete areas thereof, conditional'current means for applyingelectrical signals respectively to said distinct conductors and to saidcentral conductor for causing said discrete areas to be magnetized ineither one or the other or" said states of residual flux density, thechange in magnetic state of each of said discrete areas of ferromagneticmaterial in response to said applied electrical signals inducing avoltage in selected ones of said conductors.

13. A bistable storage element comprising at least one centralelectrical conductor, a conductive strip of ferromagnetic materialcapable of assuming bistable states of magnetic remanence representativerespectively of stored binary logical information, said ferromagneticmaterial having a preferred direction of magnetization parallel to itslongest dimension and insulated electrically at points of casual contactwith other electrical conductors and at point of casual contact betweendifferent parts of itself, said strip of ferromagnetic material beingWound in a helix around said central conductor, a plurality of distinctelectrical conductors axially spaced from one another along said centralconductor, each of said distinct conductors being positioned at rightangles to said central conductor and encircling discrete areas thereof,conditional current means for applying electrical signals re-;spectively to said distinct conductors and to said central conductorfor causing the ferromagnetic material in each of said discrete areas toassume one or the other of said bistable states of magnetic remanenceand means including selected ones of said conductors for detecting thechange in the magnetic 'rernanent state of each of said discrete areasin response to said applied electrical signals.

14. A binary data storage device comprising a multiplicity of insulatedcentral conductors, a multiplicity of conductive strips of ferromagneticmaterial each capable of assuming bistable states of magnetic remanencerepresentative respectively of stored binary logical information, saidferromagnetic material having a preferred direction of magnetizationparallel to its longest dimension of said strip, each of said strips offerromagnetic material being wound in a helix around one of saidmultiplicity of central conductors, a multiplicity of insulated secondconductors axially spaced from one another along each of saidcentralconductors, each of said second conductors being positioned atright angles to said central conductor and encircling discrete areasthereof, means for connecting in series homologous ones of said secondconductors associated respectively with different central conductors,conditional current means for selectively applying current to saidcentral conductors, said second conductors and said conductive strips offerromagnetic material for causing the ferromagnetic material in each ofsaid discrete areas to assume one or the other of said bistable statesof magnetic remanence, and means including selected ones of saidconductors for detecting a change in the magnetic remanent state of eachof said discrete areas in response to said applied electrical signals.

15. A binary data storage device comprising a multiplicity of insulatedcentral conductors, a multiplicity of conductive strips of ferromagneticmaterial each capable of assuming bistable states of magnetic remanencerepresentative respectively of stored binary logical information, saidferromagnetic material having a preferred direction of magnetizationparallel to its longest dimension of said strip, each of said strips offerromagnetic material being wound in a helix around one of saidmultiplicity of central conductors, a multiplicity of insulated secondconductors woven as a weft upon said Wrapped central conductors as aWarp, each of said second conductors encircling discrete areas of theWrapped central conductor with which it is associated, means forconnecting said second conductors into a plurality of circuits, each ofsaid circuits comprising at least one continuous turn encircling one ofsaid wrapped central conductors in series with at least one continuousturn encircling at least one other of said wrapped central conductors,conditional current means for selectively applying current to saidcentral conductors, said second conductors and said conducttive stripsof ferromagnetic material for causing the ferro- 'magnetic material ineach of said discrete areas to assume one or the other of said bistablestates of magnetic remanence, and means including selected ones of saidconductors for detecting a change in the magnetic remanent state of eachof said discrete areas in response to said applied electrical signals.

16' A binary data storage device comprising a multiplicity of pieces offerromagnetic material each capable of assuming bistable states ofmagnetic remanence representative respectively of stored binary logicalinformation, said ferromagnetic material having a preferred direction ofmagnetization substantially along the length of each of said pieces, thelength of each of said pieces being substantially greater than its widthor thickness, first conductors and second conductors interwoven withsaid pieces of ferromagnetic material and with each other wherebyapplication of a first electric current pulse to a selected one of saidfirst conductors and application of a second electric current pulse to aselected one of said second conductors will produce at the nearestjuxtaposition of said selected first conductor and said selected secondconductor a magnetizing field sufficient in magnitude and direction tocause only the discrete area of said piece of ferromagnetic materialadjacent to said juxtaposition to switch from one stable state ofmagnetic remanence to its other stable state.

17. A bistable magnetic data storage element comprising; at least onecentral conductor in an unstressed condition; at least one strip ofmagnetic material having a substantially rectangular cross-section, saidmaterial having a preferred direction of magnetization parallel to itslongest dimension and being capable of assuming bistable states ofmagnetic remanence representative respectively of stored binary logicalinformation, said strip of magnetic material being wrapped around saidcentral conductor in such fashion that the said preferred direction ofmagnetization is substantially helically disposed around said centralconductor; and at least one second conductor external to said centralconductor and to said strip of magnetic material; in such proximity andso disposed relative thereto as to be capable, by passage of electriccurrent through said second conductor, of producing a magnetizing fieldsubstantially at right angles to the magnetizing field produced bypassage of electric current through said central conductor, and meansfor selectively pulsing said conductors With electrical currents.

18. A bistable storage element comprising at least one centralelectrical conductor in an unstressed condition having wrappedtherearound at least one strip of ferromagnetic material having apreferred direction of magnetization parallel to its longest dimensionand being capable of assuming bistable states of magnetic remanencerepresentative respectively of stored binary logical information, saidferromagnetic material When wrapped around said central conductorexhibiting a preferred direction of magnetization or magnetic axissubstantially helical about said central conductor, said strip ofterromagnetic material being substantially rectangular in crosssection,the thickness of said strip of ferromagnetic material measured along aradial line from the center of said central electrical conductor beingsubstantially less than the width of said strip, a multiplicity ofsolenoidal conductors Wound around said wrapped central conductor as anaxis, the solenoids thus formed being located successively along thelength of said wrapped central conductor without overlapping each other,drive means for applying current selectively to at least certain of saidsolenoidal conductors whereby said binary information is stored alongthe length of said Wrapped central conductor.

19. A bistable storage element as defined in claim 18 furthercharacterized in that the ratio of the width of said strip offerromagnetic material to its thickness lies within the approximaterange of to l, to 250 to l.

20. A bistable storage element comprising at least one centralelectrical conductor having Wrapped therearound at least one strip offerromagnetic material having a preferred direction of magnetizationparallel to its longest dimension and being capable of attaining opposedstates of residual flux density in representing binary logical in.-formation, said strip of ferromagnetic material when wrapped around saidcentral conductor exhibiting a preferred direction of magnetizationsubstantially helical about said central conductor, said strip offerromagnetic material being substantially rectangular in cross-section,a plurality of distinct electrical conductors axially spaced from oneanother along said wrapped central conductor, each of said distinctconductors encircling said wrapped central conductor about discreteareas thereof, conditional current means for applying electrical signalsrespectively to said latter conductors and to said central conductor foreilecting the magnetization of said discrete areas whereby binarylogical information is stored in each of said areas.

21. A bistable storage element as defined in claim 20 furthercharacterized in that the ratio of the width of said strip offerromagnetic material to its thickness lies within the approximaterange of 10 to l, to, 250 to 1.

22. A bistable storage element comprising at least one centralelectrical conductor, a conductive strip of ferromagnetic materialcapable of assuming bistable states of magnetic remanence representativerespectively of stored binary logical information, said ferromagneticmaterial having a preferred direction of magnetization parallel to itslongest dimension and insulated electrically at points of casual contactwith other electrical conductors and at point of casual contact betweendifierent parts of itself, said strip of ferromagnetic material beingwound in a helix around said central conductor, said strip offerromagnetic material bein substantially rectangular in crosssection, aplurality of distinct electrical conductors axially spaced from oneanother along said central conductor, each of said distinct conductorsbeing positioned at right angles to said central conductor andencircling discrete areas thereof, conditional current means forapplying electrical signals respectively to said distinct conductors andto said central conductor for causing the ferromagnetic material in eachof said discrete areas to assume one or the other of said bistablestates of magnetic remanence and means including selected ones of saidconductors for detecting the change in the magnetic remanent state ofeach of said discrete areas in response to said applied electricalsignals.

23. A bistable storage element as defined in claim 22 furthercharacterized in that the ratio of the width of said strip offerromagnetic material to its thickness lies Within the approximaterange of 10 to l, to, 250 to 1.

24. A binary data storage device comprising a multiplicity of insulatedcentral conductors, a multiplicity of conductive strips of ferromagneticmaterial each capable of assuming bistable states of magnetic remanencerepresentative respectively of stored binary logical information, saidferromagnetic material having a preferred direction of magnetizationparallel to its longest dimension of said strip, each of said strips offerromagnetic material being wound in a helix around one of saidmultiplicity of central conductors, each of said strips of ferromagneticmaterial being substantially rectangular in cross-section, amultiplicity of insulated second conductors axially spaced from oneanother along each of said central conductors, each of said secondconductors being positioned at right angles to said central conductorand encircling discrete areas thereof, means for connecting in serieshomologous ones of said second conductors associated respectively withdifierent central conductors, conditional current means for selectivelyapplying current to said central conductors, said second conductors andsaid conductive strips of ferromagnetic material for causing theferromagnetic material in each of said discrete areas to assume one orthe other of said bistable states of magnetic remanence, and meansincluding selected ones of said conductors for detecting a change in themagnetic remanent state of each of said discrete areas in response tosaid applied electrical signals.

25. A binary data storage device as defined in claim 24 character zed inthat the thickness of each of said strips measured along a radial linefrom the center of the central conductor around which it is wound issubstantially less than the width of said strip.

26. A binary data storage device as defined in claim 25 furthercharacterized in that the ratio of the width of each of said strips offerromagnetic material to its thickness lies within the approximaterange of 10 to l, to, 250 to 1.

OTHER REFERENCES Publication 1, 1955 Western Joint Computer Conference,pages 111 to 116, published August 1955.

1. IN A BINARY DATA STORAGE DEVICE; FIRST CONDUCTORS; SECOND CONDUCTORSSUBSTANTIALLY AT RIGHT ANGLES TO SAID FIRST CONDUCTORS AND PASSINGBETWEEN ALTERNATE FIRST CONDUCTORS; AND STRIPS OF FERROMAGNETIC MATERIALWRAPPED WITH THIRD CONDUCTORS AND HAVING A PREFERRED DIRECTION OFMAGNETIZATION SUBSTANTIALLY PARALLEL TO THEIR LONGEST DIMENSION LOCATEDBETWEEN SAID FIRST CONDUCTORS AND SAID